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FreeBSD-SA-05:10.tcpdump                                    Security Advisory
                                                          The FreeBSD Project

Topic:          Infinite loops in tcpdump protocol decoding

Category:       contrib
Module:         tcpdump
Announced:      2005-06-09
Credits:        "Vade 79", Simon L. Nielsen
Affects:        FreeBSD 5.3-RELEASE and FreeBSD 5.4-RELEASE
Corrected:      2005-06-08 21:26:27 UTC (RELENG_5, 5.4-STABLE)
                2005-06-08 21:27:44 UTC (RELENG_5_4, 5.4-RELEASE-p2)
                2005-06-08 21:29:15 UTC (RELENG_5_3, 5.3-RELEASE-p16)
CVE Name:       CAN-2005-1267, CAN-2005-1278, CAN-2005-1279, CAN-2005-1280

For general information regarding FreeBSD Security Advisories,
including descriptions of the fields above, security branches, and the
following sections, please visit
<URL:http://www.freebsd.org/security/>.

I.   Background

The tcpdump utility is used to capture and examine network traffic.

II.  Problem Description

Several tcpdump protocol decoders contain programming errors which can
cause them to go into infinite loops.

III. Impact

An attacker can inject specially crafted packets into the network
which, when processed by tcpdump, could lead to a denial-of-service.
After the attack, tcpdump would no longer capture traffic, and would
potentially use all available processor time.

IV.  Workaround

No workaround is available.

V.   Solution

Perform one of the following:

1) Upgrade your vulnerable system to 5-STABLE, or to the RELENG_5_4
or RELENG_5_3 security branch dated after the correction date.

2) To patch your present system:

The following patches have been verified to apply to FreeBSD 5.3 and
5.4 systems.

a) Download the relevant patch from the location below, and verify the
detached PGP signature using your PGP utility.

# fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-05:10/tcpdump.patch
# fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-05:10/tcpdump.patch.asc

b) Execute the following commands as root:

# cd /usr/src
# patch < /path/to/patch
# cd /usr/src/usr.sbin/tcpdump/tcpdump
# make obj && make depend && make && make install

VI.  Correction details

The following list contains the revision numbers of each file that was
corrected in FreeBSD.

Branch                                                           Revision
  Path
- -------------------------------------------------------------------------
RELENG_5
  src/contrib/tcpdump/print-bgp.c                             1.1.1.5.2.1
  src/contrib/tcpdump/print-isoclns.c                            1.12.2.1
  src/contrib/tcpdump/print-ldp.c                             1.1.1.1.2.1
  src/contrib/tcpdump/print-rsvp.c                            1.1.1.1.2.1
RELENG_5_4
  src/UPDATING                                            1.342.2.24.2.11
  src/sys/conf/newvers.sh                                   1.62.2.18.2.7
  src/contrib/tcpdump/print-bgp.c                             1.1.1.5.6.1
  src/contrib/tcpdump/print-isoclns.c                            1.12.6.1
  src/contrib/tcpdump/print-ldp.c                             1.1.1.1.6.1
  src/contrib/tcpdump/print-rsvp.c                            1.1.1.1.6.1
RELENG_5_3
  src/UPDATING                                            1.342.2.13.2.19
  src/sys/conf/newvers.sh                                  1.62.2.15.2.21
  src/contrib/tcpdump/print-bgp.c                             1.1.1.5.4.1
  src/contrib/tcpdump/print-isoclns.c                            1.12.4.1
  src/contrib/tcpdump/print-ldp.c                             1.1.1.1.4.1
  src/contrib/tcpdump/print-rsvp.c                            1.1.1.1.4.1
- -------------------------------------------------------------------------

VII. References

http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2005-1267
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2005-1278
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2005-1279
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2005-1280
http://marc.theaimsgroup.com/?l=bugtraq&m=111454406222040
http://marc.theaimsgroup.com/?l=bugtraq&m=111454461300644

The latest revision of this advisory is available at
ftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-05:10.tcpdump.asc
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